We all wish the Altair guys would at least try to maintain backwards
compatibility with the community, but they have a big habit of
breaking things. This isn't the first time they've broken a more
customer facing function like tm_spawn. (The also like breaking
pbs_statjob too!).

I have access to PBS Pro and I can raise the issue with Altair if it
would help. Just let me know how I can be helpful.